Mickael Mourot

Bio: Mickael Mourot is an academic researcher from University of Lorraine. The author has contributed to research in topics: Rietveld refinement & Matrix (mathematics). The author has an hindex of 2, co-authored 6 publications receiving 17 citations.

Transformation Kinetics and Resulting Microstructure in MMC Reinforced with TiC Particles

Abstract: The phase transformation kinetics on cooling and resulting microstructures of steel-based matrix composites (MMC) reinforced with TiC particles by powder metallurgy were studied. In addition, the phase transformation kinetics of the MMC were compared to those of the same steel without TiC and consolidated in the same conditions. The presence of TiC particles strongly favors the diffusive transformations in the steel matrix of the MMC. Different complementary techniques (XRD, SEM, TEM/EDX, atom probe tomography, in situ synchrotron XRD) were performed to analyze the chemical reactivity between TiC particles and the steel powders occurring during consolidation process and further heat treatments. Composition changes in the TiC as well as in the matrix were characterized. The chemical composition after treatment in the TiC particles tends toward the thermodynamic calculations with ThermoCalc. The effect of changes in chemical composition and the role of TiC particles acting as new favorable nucleation sites are discussed in regards to the obtained results.

In Situ Structural Evolution of Steel-Based MMC by High Energy X-Ray Diffraction and Comparison with Micromechanical Approach*

Abstract: In situ high energy X-ray diffraction synchrotron was used to provide direct analysis of the transformation sequences in steel-based matrix composite (MMC) reinforced with TiC particles elaborated by powder metallurgy. Evolution of the phase fractions of the matrix and TiC particles as well as the mean cell parameters of each phase were determined by Rietveld refinement from high energy X-ray diffraction (ID15B, ESRF, Grenoble, France). In addition some peaks were further analysed in order to obtain the X-Ray strain during the cooling step. Non-linear strain evolutions of each phase are evidenced which are either associated with differences in the coefficient of thermal expansion (CTE) between matrix and TiC particle or to the occurrence of phase transformation. Micromechanical calculations were performed using the finite element method to estimate the stress state in each phase and outline the effects of differences in CTE and those of volume change associated with the matrix phase transformatio...

In Situ Structural Evolution of Steel-Based MMC by High Energy X-Ray Diffraction and Comparison with Micromechanical Approach

Abstract: In situ high energy X-ray diffraction synchrotron was used to provide direct analysis of the transformation sequences in steel-based matrix composite (MMC) reinforced with TiC particles. Evolution of the phase fractions of the matrix and TiC particles as well as the mean cell parameters of each phase were determined by Rietveld refinement from high energy X-ray diffraction (ID15B, ESRF, Grenoble, France). In addition, some peaks were further analysed in order to obtain the X-ray strain during the cooling step. Non-linear strain evolutions of each phase are evidenced, which are either associated with differences in the coefficient of thermal expansion (CTE) between matrix and TiC particle or to the occurrence of phase transformation. Micromechanical calculations were performed through the finite element method to estimate the stress state in each phase and outline the effects of differences in CTE and of volume change associated with the matrix phase transformation. The calculated results led to a final compressive hydrostatic stress in the TiC reinforcement and tensile hydrostatic stress in the matrix area around the TiC particles. Besides, the tendencies measured from in situ synchrotron diffraction (mean cell parameters) matched with the numerical estimates.

Internal Stresses in Metal Matrix Composites in Relation with Matrix Phase Transformations

Abstract: For metal matrix composites, internal stresses are a key factor for understanding the interactions between matrix and reinforcements and the mechanical properties of the composite. From in situ high energy X-ray diffraction on a steel matrix composite reinforced with TiC, the evolutions of the phase fractions and mean cell parameters of each phase during thermal treatment have been determined. In addition, a methodology is developed in order to get more information on the stress state evolutions in each phase during the treatment.

Microstructural Evolution and Strain Development in Metal Matrix Composites

Abstract: Composite materials present interesting mechanical properties. The metal provides the toughness and the particles are adding elastic stiffness, strength, hardness and wear resistance. High energy X-ray diffraction has been used to characterize the microstructure evolution of two types of MMCs (titanium and steel matrix) reinforced with TiC particles. Evolutions of mass fraction and mean cell parameters shows the effect of reinforcement on the kinetics and mechanical state of the final composites.

Effect of Al2O3 reinforcement and precipitates on corrosion behaviour of 2618 and 6061 aluminium MMCs

Abstract: The corrosion resistance features of two different Metal Matrix Composites based on 6061 and 2618 aluminium alloys reinforced by 20% Al2O3 particles by stir casting process, were studied in 3.5% Na...

In Situ Stress Tensor Determination during Phase Transformation of a Metal Matrix Composite by High-Energy X-ray Diffraction.

Abstract: In situ high-energy X-ray diffraction using a synchrotron source performed on a steel metal matrix composite reinforced by TiC allows the evolutions of internal stresses during cooling to be followed thanks to the development of a new original experimental device (a transportable radiation furnace with controlled rotation of the specimen). Using the device on a high-energy beamline during in situ thermal treatment, we were able to extract the evolution of the stress tensor components in all phases: austenite, TiC, and even during the martensitic phase transformation of the matrix.

In Situ Structural Evolution of Steel-Based MMC by High Energy X-Ray Diffraction and Comparison with Micromechanical Approach*

Abstract: In situ high energy X-ray diffraction synchrotron was used to provide direct analysis of the transformation sequences in steel-based matrix composite (MMC) reinforced with TiC particles elaborated by powder metallurgy. Evolution of the phase fractions of the matrix and TiC particles as well as the mean cell parameters of each phase were determined by Rietveld refinement from high energy X-ray diffraction (ID15B, ESRF, Grenoble, France). In addition some peaks were further analysed in order to obtain the X-Ray strain during the cooling step. Non-linear strain evolutions of each phase are evidenced which are either associated with differences in the coefficient of thermal expansion (CTE) between matrix and TiC particle or to the occurrence of phase transformation. Micromechanical calculations were performed using the finite element method to estimate the stress state in each phase and outline the effects of differences in CTE and those of volume change associated with the matrix phase transformatio...